Many electrical contacts or terminals have been designed for receiving or mating with a male tab or blade contact. Such terminals often are used in tap connectors for making a T-connection to an insulated electrical wire. In such connectors, one end of the terminal includes an insulation displacement, wire-receiving portion, and the opposite end of the terminal includes a mating or blade-receiving portion. Design considerations for these terminals must take into account the differing requirements for both types of connections. Factors which affect the design of the insulation displacement end of the terminal include providing sufficient resistance to wire pull-out, and providing sufficient integrity in the material thickness to displace the insulation without cutting the conductors and without allowing the insulation displacing slots to open. Factors which affect the design of the blade-receiving end of the terminal include selecting a material thickness which does not take a set and which carries maximum current. General design considerations, such as minimizing material waste and simplifying the design and manufacture of the terminals, also are important. Because of the number of factors to be considered, most tap connectors often use relatively complex stamped and formed terminals that include formed blade-receiving slots which typically utilize a relatively large amount of material and are more complicated and difficult to maintain in terms of tolerances than stamped slots.
One type of stamped and formed terminal for connecting an insulated wire to a blade contact and which utilizes a stamped blade-receiving slot is disclosed in U.S. Pat. No. 4,527,852, assigned to the assignee of the subject invention. The terminal is generally U-shaped and includes a pair of leg portions joined by a bight portion. The leg portions define a longitudinal terminal axis generally centrally therebetween. Free ends of the leg portions are provided with insulation displacement slots for electrically connecting the terminal to the insulated wire without stripping or crimping the wire. The bight portion of the terminal includes a blade-receiving slot extending into the leg portions and defining a bifurcated contact formation for receiving the blade contact.
However, one of the problems with the U-shaped terminal described is that it does not provide a simple means for locking to a blade contact when in mated condition. Blade contacts often have standard dimensional features including locking means formed on the blade contact itself. One type of locking means is provided in the form of a recess or detent in one or both sides of the blade contact generally along a centerline thereof. Another type of locking means is provided in the form of an aperture extending through the blade contact. Such a feature allows the blade contact to positively lock to a mating terminal. This locking feature provides high reliability between the terminals and assures the continued connection thereof particularly in high vibration applications involving motors or constant movement. In order to lock the blade contact to a mating terminal, locking projections must be provided on the terminal for protruding into the locking recess(es) or aperture of the blade contact. Heretofore, it has not been possible to provide generally U-shaped terminals with adequate blade-locking means and to still maintain a reliable electrical connection thereto.
In particular, if a locking projection was to be provided in the blade-receiving slot of one of the leg portions of the U-shaped terminal described above, the blade terminal would not be centered within the terminal and therefore may not engage both leg portions of the terminal, thus reducing the contact surfaces between the terminals and minimizing the current-carrying capability of the mated conductors. If the locking projection was provided in the blade-receiving slot at the bight portion of the terminal, along the longitudinal terminal axis, the insertion depth of the blade contact into the terminal may not be sufficient and, again, the current-carrying capacity may be compromised. Furthermore, providing the locking projection directly at the tip or bight portion of the terminal prevents the use or provision of a lead-in mouth for facilitating mating of the terminal and blade contact, which is very advantageous in most applications.
The present invention is directed to solving these problems by providing a unique configuration of a generally U-shaped terminal for receiving a blade contact, which includes a locking feature for the contact, while maximizing the current-carrying capacity of the terminal.